Benjamin f



(No Model.)

B. F. WILLISTON.

DASH POT EOE STEAM ENGINES. No. 328,909. Patented Oct. 20. 1885.

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UNITED STATES BENJAMIN F. VILLISTON, OF VVESI BAY CITY, MICHIGAN, ASSIGNOR OFV PATENT OFFICE.

ONE-HALFTO SAMUEL A. PLUMMER, OF SAME PLAGE.

DASH-POT FOR STEAM-ENGINES,

SPECIFICATION forming part of Letters Patent No. 328,909, dated October 20, 1885.

Application tiled January 3, 1885.

To all whom it may concern.-

Be it known that I, BENJAMIN F. WILLIS- troN, a citizen of the United States, residing at West Bay City, in the county of Bay and State of Michigan, have invented certain new and useful Improvements in Dash-Pots for Steam-Engines; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it apper'tains to make and use the same, reference being had to the accompanying drawings and to the letters and figures of reference marked thereon.which form a part of this specification.

My invention relates to improvements in dash-pots used to force a lifted steam-valve quickly back to its seat and to form a cushion to act upon the said valve to prevent its clashing upon its seat; and the object of my invention is to provide a means of forming a suitable pressure upon the valve by the action of steam, and also to form a cushion to receive the Aforce of the closing valve and to allow the valve to gently close upon its seat after having been quickly started and propelled downward, and to prevent the noise and wear and injury caused by the valve closing directly upon its seat. I accomplish these objects by means of the mechanism illustrated in the accompanying drawings, in which Figure 1 is a transverse vertical section Vof my improved dash-pot, also of an ordinary steam-chest and puppet-valve. Fig. 2 is a similar View of the same,with also an expansion-chamber added.

Similar letters refer to similar parts throughout the several views.

arepresents asteam-chest; b, alii'ting valve. c is the seat of the valve, and d the valve-stem, which is pivoted to the beam e, which is arranged in the usual manner to lift the valve and close the same at the proper time.

h is a small steam-cylinder suitably supported on or near the steam-chest a, and provided at one end with the pipe o, and the opposite end is provided with a packing-box, t. A piston-head, g, provided with suitable means of making a steam-tight joint around the same, as the packing-rings i, is placed within the cylinder h, dividing the cylinder into the chambers k and a, and is provided with a piston-rod, f, which passes through the packing- Serial No. 151.906. (No model.)

box t and at its outer end is pivoted to the beam e. Near the upper part of the cylinder h is inserted the steam-pipe u. This pipeu is provided at a suitable point with a valve, Q2, and has its opposite end connected with the steam-chest a, or some part of the steam pipe or boiler, so that steam may be admitted to the chamber k. Connected to the cylinder h by means of the pipe 0 is the chamber p, provided at its lower part with the waste-pipe r and valve s.

rlhe piston-head g is -provided with a port or passage, m, which passes entirely through the said piston-head for the admission of steam from the chamber k to the chamber n, or in the opposite direction, as required. The size of this holemJ is regulated to correspond to the size of the cylinder h, as a very small hole is required to admit the proper pressure of steam to the lower chamber, n, and expansion-chamber p.

Before the engine is started the valve i; is opened to admit the proper amount of steam to the cylinder h, and the steam passing through the passage m fills also the expansion-chambersp and n, and as the valve b is lifted from its seat for the admission of steam to the cylinder of the engine the piston g is lifted to the upper part of the cylinder l, and the pressure inthe chambers n and p reduced., the port or passage m being of such size as to prevent the passage of sufficient steam to give the chambers n and expansion chambers p an equal pressure with the chamber 7c as the piston rises, the pressure in the chamber 7c being at all times equal, as the steam in the chamber Ja, when the piston is raised, is forced into the boiler through the pipe u, and when the valve b is released from the lifting power the steampressure of the boiler passing through the pipe u acts to force the piston-head g to the opposite end of the cylinder h, and with this power the valve b is quickly forced toward its seat c, and meanwhile the steam from the chamber 7c has been passing through ,the small port or passage m into the chamber n and expansionchamber p, so that when the valve b shall have nearly reached its seat c the pressure in lthe expansion-chamber h and chamber n will have been more than that in the chamber k, and the motion of the valve b is arrested,

ICO

and the pressure in the chambers n and p isreduced by the steam passing again through the opening m into the chamber 7c and also through the wastepipe r, a slight opening being left by the valve s for the purpose of adjusting the pressure in the chambers n and p, as, should the valve s be entirely closed, the motion of the piston g would be 'arrested before the valve b had reached its seat, as the passage m would not allow the requiredquantity of steam to pass to the chamber k within the proper time; and if the valve s is given a larger opening than required. the valve b will clash upon its seat, so that to adj ust the pressure in the chamber n and p the valves is given a suitable opening, to allow the valve b to close gently upon its seat, when the machinery will operate without noise or clashing, and without adjusting for different working-pressure, as any variation of pressure of the steam in the chamber k is given a corresponding variation in the chamber n and expansion-chamber h, and the effect upon the Valve b is the same.

In Fig. l the device is shown with the expansion-chamber p omitted, the cylinder h being constructed with sufficient length to provide the chamber n with proper capacity to form a suitable expansion-chamber, and the waste-pipe r is then connected directly to the lower part of the chamber a, and, with a proper adjustment of the valve s, the effect produced will be the same as before described.

The expansion-chamber p is designed to be used in connection with the two valves of an engine, if necessary, as by connecting two cylinders h with one expansion chamber, only one valve need be used to adjust the pressure in both cylinders. I also find it beneicial in some cases to reduce the entrance of the pipe o to the cylinder h,- as shown by anges o', so as to partially retard the passage of steam from the chamber p to the chamber h, and form an easier and more flexible pressure beneath the piston-head g.

The waste-pipe r and. valve s are also useful to relieve the chambers n and p from the accumulation of water formed from thecondensation of the steam used within the said chamber, as the slight opening of the valve s allows the water to drip therefrom as the apparatus is working.

What I claim as my invention, and desire to secure by Letters Patent of the United States,l

l. In a dash-pot, the combination of a steamchest, and a valve within the chest, with a cylinder placed outside of and near the said chest, and provided with a packing-box at one end, and a waste-pipe and valve at the opposite end, a piston-head dividing said cylinder into two chambers, and provided with a passage for admitting steam from one of said chambers into the other, a piston connected with the said piston-head at one end, and with the opposite end connected with means of operating the said valve within the said steamchest, means, as described, of admitting steam to the said cylinder, and means, as described, of regulating the pressure in one chamber of the said cylinder. substantially as and for the purpose specified.

2. In a dash-pot, the combination of the steam-cylinder h, provided at one end with a packing-box, and at the opposite end with a waste-pipe and valve, with a piston-head, g, provided with the passage m, the piston f, passed through the said packing-box and connected at its inner end with the said pistonhead, and with its opposite end connected with means of operating upon the valve b, and

the steam-pipe u, provided with the valve v,

substantially as described.

3. In a dash-pot, the cylinder h, provided with the packing box t, the pistonhead. g, having the steam-passage m, the piston f, and steam-pipe u, provided with the valve c, in combination with vthe expansion-chamber p, attached to the said cylinder by the pipe o, and provided with the waste-pipe r and valve s, substantially as shown, and for the purpose set forth.

4. In a dash-pot, acylinder having apistonhead forming two chambers within the cylinder, and means, substantially as described, for admitting steam from one of the said chambers to the other, in combination with a steampipe connected with the said cylinder, and arranged to produce a steady pressure of steam within one of the said chambers, and awastepipe and valve connected with the other of the said chambers for producing a variable pressure therein, substantially as and for the purpose set forth.

In testimony whereof I affix my signature in presence of two witnesses.

BENJAMIN F. WILLISTON.

Witnesses:

I. E. THOMAS, F, W. INGERsoLL. 

